\section{Conclusion and Future Works}
\label{sec:conclusion}
In this project, we achieved realtime volume rendering with global illumination effects with only a little overhead. Current limitation is that it only support the rendering of isotropic materials under directional lights. In future works, we will extend the directional lighting environment to general lighting and also extend the shading to anisotropic materials with limited extra storage and processing time. We will further investigate its applications in scientific and medical visualization. It is possible to separate the global volumetric shadow and multiple scattering effects in order to apply them individually. 